Industrial buildings and office buildings are typically designed so as to be subdivided into ‘fire compartments’ in order to provide passive fire protection for limiting or retarding the spread of fire, smoke, poisonous gases and/or damaging heat in case of a fire. For this purpose, the doors and windows that are utilized in the building must have predetermined fire resistance properties, which are ascertained by performing a standard fire resistance test on the structural element. According to the results of the standard fire resistance test, the structural element is classified into a fire resistance class or rating, e.g., D30, D60, D90. Herein, the alphabetic letter indicates the usage (e.g., D=door) and the number indicates the length of time in minutes that the structural element has withstood the heat applied thereto during the standard fire resistance test.
The standard fire resistance test provides an indication of how long the structural element will enable the fire compartments to remain securely separated and air-tight under standard fire conditions, so that, e.g., gases generated during a fire are prevented from reaching the side of the structural element facing away from the fire. It is also important that the temperatures on the side facing away from the fire are not permitted to rise for the prescribed period time to a point that will cause the ignition of easily-ignited materials located there.
Aluminum composite profiles or frames are often utilized in window, door and façade elements installed in industrial and office buildings. Since the aluminum itself will start to melt at the temperatures associated with a fire, a cooling medium (e.g., intumescent materials and/or water-absorbent materials such as gypsum-alum, see e.g., DE 44 43 762 A1 or its English counterpart U.S. Pat. No. 5,694,731) is often disposed in the composite profile prior to installation in the building. The aluminum composite profile is normally comprised of at least two aluminum profile parts, the aluminum inner frame and the aluminum outer frame. One or more insulating strips connect the aluminum inner frame and the aluminum outer frame while also providing a thermal separation of the two frames, thereby reducing heat conduction from the inner frame to the outer frame and vice versa during normal usage and thus improving the insulating characteristics of the structural element as a whole. In composite profiles having increased fire resistance properties, the insulating strips connecting the aluminum inner frame and the aluminum outer frame are usually not exclusively manufactured from thermoplastic synthetic materials. Either the thermoplastic synthetic material is replaced with a non-melting, thermosetting synthetic material, or metal bridges, e.g., steel brackets, are utilized, at least sectionally.
However, thermosetting synthetic materials have the disadvantage of poor workability. Thermosetting synthetic materials, in particular, are difficult to cut properly when the composite profile must be sawed into segments of specific lengths during the finishing process. The use of steel brackets or other metal bridges has the disadvantage of requiring a large amount of manual labor.
Another known approach utilizes a plurality of aluminum bridges that conduct a defined amount of heat from the fire side to the side facing away from the fire. This approach is disadvantageous because heat is also continuously conducted across the aluminum bridges during normal usage. Thus, such an approach reduces the thermal separation of the aluminum inner frame from the aluminum outer frame and thus reduces the insulating properties of the structural element as a whole.
EP 1 024 243 A2 describes a composite profile having a fireproof, supplemental element in the form of a metal bracket that is adhered onto the insulating strip and in the normal state extends in receiving spaces of the outer profile parts.
EP 1 182 317 A2 describes a composite profile having fire resistance properties, in which the insulating strip is comprised, in sections, of metal instead of a thermoplastic synthetic material.
EP 0 785 334 B1 describes a composite profile, wherein the outer profile parts are not connected by fireproof insulating strips. A fireproof, shaped material is connected with the outer profile parts in a form-fitting manner.
A composite profile having fire resistance properties is known from DE 44 43 762 A1 and its English counterpart U.S. Pat. No. 5,694,731, wherein the insulating strips are either perforated metal rails or perforated synthetic material rails, in which the synthetic material is replaced, in sections, with bridge strips made of metal. A fire-resistant strip can be provided on an insulating strip.
Further composite profiles having fire resistance properties are known from EP 1 327 741 A2 and DE 44 04 565 C1/EP 667 439 B1.